# cupyx.scipy.fft.next_fast_len¶

cupyx.scipy.fft.next_fast_len(target, real=False)[source]

Find the next fast size to fft.

Parameters
• target (int) – The size of input array.

• real (bool) – True if the FFT involves real input or output. This parameter is of no use, and only for compatibility to SciPy’s interface.

Returns

The smallest fast length greater than or equal to the input value.

Return type

int

Note

It may return a different value to scipy.fft.next_fast_len() as pocketfft’s prime factors are different from cuFFT’s factors. For details, see the cuFFT documentation.